'Which class is better when they can reliably get a long rest in between most encounters
is a totally different question to 'which class is better when the adventuring day consists oaround 6 encounters and around 2 short rests?'
- If you can reliably nova via the DM being unable or unwilling to police the adventuring day, and it routinely consisting of a single encounter, then long rest dependent classes and subclasses are better (for obvious reasons).
- If your DM does police the adventuring day and roughly cleaves to the (6 or so encounter/ 2 or so short rest) median, then classes more or less balance out.
- If your DM routinely pushes longer adventuring days (via gritty rest variants or whatever) where long rests are rare, and short rests quite common, then Short rest dependent classes and subclasses are better (for obvious reasons).
Classes gain the majority of their oomph via short and long rest resources (spell slots, Ki points, rages, SP, superiority die, wild shapes channel divinity, second wind, action surge, indomitable, Bardic inspiration etc) and some classes are very short rest dependent, while others are very long rest dependent (with the Rogue being largely rest neutral).
You cant meaningfully discuss which class (or subclass) is 'more powerful' without that context, and it varies from table to table depending largely on the DM's management of the adventuring day (and of course, player skill).